@page{size:A4 portrait;margin:0}html,body{margin:0;padding:0;width:210mm}.print-area{display:block}.page{width:210mm;height:297mm;padding:15mm 20mm;box-sizing:border-box;background-color:#fff;display:flex;flex-direction:column;position:relative;overflow:hidden}@media screen{body{background-color:#f0f0f0;display:flex;flex-direction:column;align-items:center}.page{margin:20px 0;box-shadow:0 0 10px #0000001a}}@media print{body,.print-area{width:210mm}.page{margin:0;box-shadow:none;page-break-after:always;page-break-inside:avoid}}.header{text-align:center;margin-bottom:60px}.title{font-size:28pt;font-weight:700}.problems-grid{display:grid;grid-template-columns:1fr 1fr;grid-template-rows:repeat(10,1fr);flex-grow:1;gap:10px 100px;padding:0 5mm;position:relative}.page-subtraction .problems-grid,.page-add-10 .problems-grid{padding-left:20mm}.page-subtraction .problems-grid:before,.page-add-10 .problems-grid:before{left:calc(50% + 7.5mm)}.problems-grid:before{content:"";position:absolute;top:0;bottom:0;left:50%;width:1px;background-color:#000;transform:translate(-50%)}.problem{font-size:24pt;font-family:Courier New,Courier,monospace;font-weight:700;display:flex;align-items:center;justify-content:flex-start;letter-spacing:2px;white-space:nowrap}.blank-box{display:inline-block;width:1.6em;height:1.6em;border:2px solid black;margin:0 15px;vertical-align:middle}.minus-sign{font-size:26pt;font-weight:900;margin:0 8px;display:inline-block}.hundred-cells-container{width:100%;display:flex;flex-direction:column}.row-table{width:100%;border-collapse:collapse;margin-bottom:4mm;table-layout:fixed;page-break-inside:avoid}.row-table:last-child{margin-bottom:0}.row-table td{border:1.5px solid #000;text-align:center;vertical-align:middle}.row-table td.op{border:none;font-size:22pt;font-weight:700;width:12mm;text-align:right;padding-right:5px}.row-table td.left-num{border:2px solid #000;background:#f9f9f9;font-size:20pt;font-weight:700;width:14mm}.row-table td.top-num{background:#f9f9f9;font-weight:700;height:7mm;font-size:14pt}.row-table td.empty-cell{height:12mm}.page-footer{text-align:center;font-size:10pt;color:#666;padding-bottom:10mm}body{margin:0;padding:0;background-color:#f0f0f0;font-family:Helvetica Neue,Arial,Hiragino Kaku Gothic ProN,Hiragino Sans,Meiryo,sans-serif}@media print{body{background-color:#fff}.no-print,.controls{display:none!important}}.controls{padding:20px;background:#fff;border-bottom:1px solid #ccc;display:flex;justify-content:center;gap:20px;position:sticky;top:0;z-index:100}button{padding:10px 20px;font-size:16px;cursor:pointer;background-color:#007bff;color:#fff;border:none;border-radius:4px}button:hover{background-color:#0056b3}